I’m trying to make brushes for vegetation (e.g. leaves), and it appears my only options for brush tips are to use color as mask, which appears to convert the value portion of the HSV of the image used into alpha, or I can just have the original color. The feature I’m proposing is an option to use alpha values in the image as the alpha, and preserve the value. This way I can have shading and outlines in the brush, but still choose the color. Currently, any shading in the image used to create the brush gets turned into alpha, which isn’t what I want.
If this is difficult (like it breaks compatibility for brush tip images), then an alternative method would be to add a brush on top, like the current masked brush, but that is an overlay instead of masking the brush. This way I can have the main brush tip be the color mask, and the other be a detail overlay. This would actually be the more versatile option, since it would allow the overlay to have different colors, rather than just modifying the value.
If the second option is taken, the overlay brush would need to be able to share the rotation, size, etc of the main brush, so you don’t get weird effects (though it could be interesting to leave that as an option).